NEWBORN SCREENING
A 1-month-old fair-haired, fair-skinned baby presents with projectile
vomiting of 4 days’ duration. Physical exam reveals a baby with eczema
and a musty odor. Which screening test would most likely be abnormal?
Every newborn is screened before discharge or day 4 of life. It is more reliable if
done after 48 hours of oral feedings (substrates for metabolic diseases).
The total diseases screened are determined by the individual state. Some
examples:
Phenylketonuria (PKU) Classic Galactosemia
Defect Phenylalanine hydroxylase;
accumulation of PHE in body
fluids and CNS
Gal-1-P uridylyltransferase deficiency;
accumulation of gal-1-P with injury to kidney,
liver, and brain
Presentation Mental retardation, vomiting,
growth retardation, purposeless
Jaundice (often direct), hepatomegaly, vomiting,
hypoglycemia, cataracts, seizures, poor feeding,
Phenylketonuria
Tyrosinemia
21-hydroxylase deficiency
Galactosemia
Hb SS
Hb C
Hypothyroidism
Cystic fibrosis
Table 1-4. Two Newborn Screening Diseases*
movements, athetosis, seizures poor weight gain, mental retardation
Associations Fair hair, fair skin, blue eyes,
tooth abnormalities,
microcephaly
Predisposition to E. coli sepsis; developmental
delay, speech disorders, learning disabilities
Other
comments
Normal at birth; gradual MR
over first few months
May begin prenatally—transplacental
galactose from mother
Treatment Low PHE diet for life No lactose—reverses growth failure, kidney and
liver abnormalities and cataracts, but not
neurodevelopmental problems